Stitch-forming mechanism for buttonhole-sewing machines.



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PATBNTED JULY s, 1906. D.N0BLE & J. S. PINCH. STITCH FORMING MBGHANISM PoR BUTTONHOLB SEWING MACHINES.

APPLICATION FILED JAN. 7, 1905.

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nu: Numus Ps No. 825,152.V PATENTED JULY-3, 1906.

' D. NOBLE & J. S. IINGH.

STITCH FORMING MEGHANISM POR BUTTONHOLE SEWING MACHINES.

A-PPLIUATION FILED JAN, 7. 1905.

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WITNESSES: \L J Y www, L

ATTORNEY No. 825,152. 4 PATENTED JULY 3, 1906. D. NOBLE L J. S. IINGH.

STITCH IORMING MECHANISM FOR BUTTONHOLE SEWING MACHINES.

- APPLICATION FILED JAN. 7, 1905.

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ATTORNEY No. 825,152. PATENTED JULY 3, 1906. D. NOBLE & J. S. FINC'H.

STITCH FORMIN-G MEGHANISM FOR BUTTONHOLE SEWING MACHINES. AP'PLIUATION FILED JAN. 7. 1905.

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IINITEI) STATES PATENTl OFFICE.

DONALD NOBLE AND JOHN S. FINCH, OF BRIDGEPORT, CONNECTICUT, ASSIGNORS TO WHEELER & WILSON MANUFACTURING COMPANY, OF BRIDGEPORT, CONNECTICUT, A CORPORATION OF CONNECTICUT.

STITCH-FORMING MECHANISM FOR-BUTTONHOLE-SEWING MACHINES.

Specicaton of Letters Patent.

Patented July 3, 1906.

Application led January 7,1905. Serial No. 240,067.

To @ZZ whom, it may concern:

Be it known that we, DONALD NOBLE, a subject of the King of Great Britain, and JOI-IN S. FINCH, a citizen of the United States, residing at Bridgeport, in the county of Fairfield and State of Connecticut, have invented a certain new and useful Improvement in Stitch-Forming Mechanisms for Buttonhole- Sewing Machines, of which the following is a full, clear, and exact description.

Our invention relates to buttonhole-sewing machines which employ an upper and under thread.

The invention consists in a sewing-machine of the class described in which is employed a thread pull-0H operatively mounted beneath the throat-plate and adapted to engage the under thread on its way from the bobbin to the material, said pull-off being actuated to draw a predetermined quantity of 'under thread from the bobbin at alternate stitches and the quantity of thread so drawn off being varied for the respective sides of the buttonhole, so that a Greater quantity may be drawn off for one side than for the other, with the purl lying close to or within the buttonhole-slit, all as we will proceed now more particularly to set forth and finally claim.

In the accompanying drawings, llustrating the invention, in the several figures of which like parts are similarly designated, Figure 1 is a front elevation, partly in section, of a buttonhole-sewing machine equipped with our invention. Fig. 2 is a bottom plan view of such machine. Fig. 3 is a horizontal section or plan view taken in the plane of the line A B, Fig. 1. Fig. 4 is a cross-section taken in the plane of line C l), Fig. 2. Fig. 5 is a bottom plan view. Fig. 6 is a top plan view, and Fig. 7 is a side elevation of the thread-engaging finger and its supportinglever. Fig. S is a perspective view of the thread-guard plate. Fig. 9 is a top plan view of a modification of the mechanism for actuating the thread-engaging finger-lever- Fig. 10 is a development of the cam for actuating the thread-drawing devices. Fig. 11 is a similar View of a modification of this cam.

A machine embodying our invention may be provided with any usual or approved mechanism, such as that shown, for presenting the material to the action of the stitchforming mechanism, so as to form the two lines of overseam-stitches by a movement of the mechanism in one direction for overseaming one side of a buttonhole and then in the opposite direction for overseaming the other side of the buttonhole.

1 is the frame or bed-plate of the machine, surmounted by the usual overhanofing arm 2, within which is suitably ournaled the upper or needle-actuating shaft 3.

4 is the needle-bar, mounted within a Swinging gate or frame 5, pivoted to the arm in the usual or anyapproved manner, so as to permit of the lateral or zigzag movements of the needle-bar to form the overseam-stitches- The needle-bar 4 is operatively connected with the shaft 3 by the usual link connection 6.

7 is a segment-lever, pivoted to the overhanging arm at 8 and operatively connected with a switch-cam 9, mounted on the shaft 3, whereby said lever is oscillated at each alternate revolution of the shaft 3 in the manner usual for positioning the needle for overseam-stitches.

10 is a link, one end of which is pivoted to the needle-bar frame 5 in the usual manner, while the other end is pivoted around a stud 11, formed on a slide-block 12, fitted within the undercut arcuate groove 13 in the seg ment-lever 7.

14 is the cloth-clamp mounted and actu ated in the usual or any approved manner, and .15 is a disk or wheel which forms a portion of the clamp-actuating mechanism and upon which is mounted a cam 16, adapt ed to coperate with a lever 17. This lever 17 carries at one end a roller 18, which tracks upon the cam 16, and at its other end it is secured by a pinch-joint 19 to a vertically-disposed rock-shaft 20, mounted in a bracketbearing 21, secured, as by a screw 22, to any suitable part of the machine. The lower end of the shaft 20 has fixed to it a crank 23. By means of the pinchejoint 19 the lever 17 may be adjusted upon the shaft 20, so as to vary its angular relation to the crank 23. The crank 23 is connected by a link 24 with the lever 25, the rear end of which is provided with an inverted-T-shaped block 26, secured thereon by a nut and screw 27, said block being arranged to work freely within an undercut arcuate groove 28 in a rock-lever 29. This rock-lever is fulcrumed substantially midway between its ends in a vertical bear IOO IOS

ing 30, and it is provided at one end witha roller or other device 31, which tracks in a groove of the surface-cam 32, mounted upon a counter-shaft 33, which is supported in arms 34 of the bracket on which the bearing 30 is formed. This bracket as a Whole has a supporting-plate 35 to receive screws 36, by which it may be fastenedto the under side of the bed-plate. As shown in Figs. 2 and 10, the cam 32 has a single lump, so as to make but one vibration of the lever 29 in its rotation and to draw the thread at every alternate stitch, while, as shown in Fig. 11, the cam may be made with two lumps of different sizes and two dwells, so as to draw alternate long and short lengths of thread at each revolution, as will appear more particularly hereinafter.

The front end of the lever 25 is adjustably connected by a slide-block 37 and pinch-nut 38 with a lever 39,`pivoted at 40 to the under side of the bed of the machine, and to this leveris secured at its free end a thread-engaging finger 41, having an opening 42 in the form of a transverse slot. The thread-engaging finger and its lever 39 constitute the pull-off hereinafter referred to. The thread-engaging finger 41 is adjustably secured to the lever 39 by means of a set-screw 43, and slot 44. It will be understood, of course, that the vibration of the lever 29 will be imparted to the lever 25 and by that in turn to the lever 39 in such way that the thread-engaging finger will have a transverse movement across the path of movement of the needle.

The counter-shaft 33 is journaled in the bracket parallel with the under or hookdriving shaft 45, and upon one end of countershaft 33 is secured a spur-gear 46, which intermeshes with apinion 47, tight on the hookdriving shaft 45. The proportions 'of the gears 46 and 47 are such that the countershaft 33 and cam 32 thereon will be revolved once during two revolutions of the hookdriving shaft 45, and the shape of the groove in' the cam 32 is such as to cause the lever 29 to be oscillated back and forth between each alternate descent of the needle.

A 48 is a thread-guard plate secured to the under side of the bed-plate and extending in close proximity to the needle-aperture 49 in the throat-plate 50, and said thread-guard plate is provided with a needle-aperture or thread-guide opening 51.

The opening or eye 42 in the thread-engaging finger 41 when said finger is at rest at the downward limit of the needle-stroke is in alinement with the apertures in said throatplate and thread-guard plate. Said threadengaging finger works in a field directly beneath the throat-plate and between the latter and said thread-guard plate 48.

f52-is a coiled spring, one end of which is secured to the crank 23, While the other end is attached tothe bed-plate, said spring servylows: As shown in Fig. 2, the parts are adjusted tovdraw an equal amount of thread from the bobbin for both sides of the buttonhole, the relative adjustment of the lever 17 and crank 23 by means of the pinch-joint 19 being such as to cause the slide-block 26 to be moved to points equidistant from the fulcrum of the segment-lever 29 and at opposite sides of said fulcrum by the action of the cam 16 to position said slide-block for the respective vsides ofthe buttonhole. Motion being imparted to the cam 32 through the gears 46 47 the segment-lever 29 will be given a quick vibration back and forth at every second descent of the needle, and by reason of the position which the slide-block 26 occupies with respect to the fulcrum of said segment-lever the lever 39 and thread-drawing finger 41 mounted thereon will be given a movement to the right of the central position it occupies in Fig. 2 and back again, such movement taking place preferably between the time when the needle withdraws from the throat-plate and before the take-up 53 (of any approved construction) finishes the stitch. After one edge of the buttonhole has been overseamed and before oversearning the other edge the action of the cam 16 will cause the slideblock 26, through the link connection 25 24 23 and lever 17, to be shifted to the opposite side of the fulcrum of said segment-lever, whereby the parts will be positioned for drawing thread for the other edge of the buttonhole, such shifting action of the slide-block 26 causing the action of the thread-drawing finger 41 to be reversed with respect to the zigzag movements of the needle-bar, thereby preserving the proper conditions for the formation of the peculiar stitch sought, for it will be observed that the long-loop stitch is or should be tightened as the needle is about to enter the slit position and not when entering the bight position, and were such drawing action of the thread not reversed with respect to the zigzag movement of the needle the long-loop stitch would be tightened by the take-up when the needle was about entering the slit when overseaming one side of the buttonhole, and while overseaming the other side of the hole such long-loop stitch would be tightened by the take-up at a time when the needle was about to enter the bight, a condition unfavorable to the production of the peculiar kind of buttonhole sought. By

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moving the block 37 to various positions in the groove in the thread-drawing lever 39 more or less thread may be drawn from the bobbin for bights of various widths.

By reason of the adjustments provided for by means of the pinch-joint 19 various adjustments of the slideblock 26 may be obtained to alter the action of the thread-drawing finger. For instance, the position of said block 26 may be so changed in lever 29 as to vary the throw of the lever 39 of the thread-drawing finger 41 through lever 25 to cause said finger to draw a greater quantity of thread for one side of the buttonhole than for the other. Also by reducing the effective action of the cam 16 such ad`ustments may be obtained as to draw threa upon one side of the hole only, in such case said block 26 being merely moved from its thread-drawing position to a point concentric with the fulcrum of the segment-lever 29. The reducing of the effective action of the cam 16 above mentioned may be effected by providing the cam with smaller steps between the dwells, or, as shown in Fig. 9, {the same result may be obtained by providing the bracket-bearing 21 with a lug 53, having in it a set-screw 54, adjustable with relation to an ear 55, formed on the lever 17, so that by adjusting the set-screw 54 the length of throw of the lever 17 may be varied.

When the lever 17 is adjusted at the reuired angle with relation to the crank 23, so t at the slide-block 26 moves equidistantly to points on opposite sides of the fulcrum of lever 29, then by the action of the cam 16 on lever 17 an equal length of thread will be drawn off for each side of the buttonhole. This length of thread drawn off may be increased or diminished by changing the angular relation of the lever 17 and crank 23, so that in stitching one side of the buttonhole the block 26 would be at a greater distance from the fulcrum of the lever 29 than when stitching the other side of the buttonhole, the

proportional lengths of thread so drawn remaining the same whether a wide or narrow bight is being used and variations in the bight being effected by moving the block 37 in the lever 39 toward or from the fulcrum of said lever.

In pulling 0H thread at alternate stitches by the mechanism described it is immaterial whether the thread be drawn at a point between the bobbin-case'leader 56,which may or may not have a thread-eye in its end, and the throat-plate or between such leader and the point where such thread leads out of the bobbin-case. Furthermore, by employing a cam otherwise shaped from the one illustrated in Fig. 2 and of a contour such as to effect movements at each stitch a length of thread suitable for the formation of the long loop may be drawn from the bobbin at each alternate stitch and also a length of thread suitable for the-formation of the short loop may be drawn from the bobbin. .In other words, instead of cam 32 of the contour shown in Fig. 10 we may use a cam 32X, so shaped, as ilustrated in Fig. 11, with two dwells and two lumps or steps, as to draw alternate long and short lengths of thread from the bobbin for the formation of the peculiar stitch required, as will be readily understood.

The under thread leads out of the bobbincase through the thread-guard plate 48, thence through the thread-drawing finger 41, and thence up through the throat-plate aperture 49 to the material.

I/Vhile we prefer to employ the threadguard plate 4S to assist in drawing the thread from the bobbin, in some constructions of loop-takers such plate is unneccessary, and we do not, therefore, wish to be restricted to its use. Furthermore, while we have shown and described our invention as applied to a buttonhole-sewing machine of the variety which zigzags the needle to form the overseam-stitches, nevertheless we do not .wish to be limited thereby, since our improvements are equally applicable to buttonholesewing machines which do not zigzag the needle, but rely upon the movements of the cloth-clamp to position the material for the overseam-stitches.

1. In a buttonhole-sewing machine, employing an upper and an under thread, a throat-plate, and means for feeding the material, 1n combination with stitch-forming mechanism including a bobbin, and a thread pull-o operatively mounted beneath the throat-plate and adapted to engage the und er thread on its way from the bobbin to the material, means for actuating said thread ulloff, whereby a predetermined quantity of under thread is drawn from the bobbin at alternate stitches, and adjustable means for varying the quantity of thread so drawn for the respective sides of the buttonhole, whereby a greater quantity of thread may be drawn for one side of the hole than is drawn for the other.

2. In a buttonhole-sewing machine, of the character described, the combination of a rotary cam, a rock-shaft, a lever on said rockshaft in contact with said cam, a crank on said rock-shaft, a lever connected to said crank, an under-thread pull-ofi connected with said crank-connected lever, a rock-lever to which the crank-connected lever is attached, and means to rock said rock-lever.

3. In a buttonhole-sewing machine, of the character described, the combination of a rotary cam, a rock-shaft, a lever adjustably mounted upon said rock-shaft and contacting with the cam, a crank on said rock-shaft, a lever connected to said crank, an underthread pull-off, comprising a lever and a thread-engaging finger, connected with said IOO crank-connected lever, a rock-lever, a shiftmg connection between the crank-connected lever and the rock-lever, and means to rock said rock-lever.

4. In a buttonhole-sewing machine, of the character described, the combination of a rotary cam, a rook-shaft, a lever on said rockshaft actuated by said cam, and a crank on said rock-shaft, an under-thread pull-off, means for operating and controlling the pulloff including connections between said crank and pull-off, and means to adjust the angle between the rock-shaft lever and the crank on the rock-shaft.

5. In a buttonhole-sewing machine, of the character described, the combination of a rotary cam, a rock-shaft, a lever adjustable on said rock-shaft, a crank fast on said rockshaft, a lever connected to said crank, an under-thread pull-off arranged in the path of movement of the needle, a shiftable connection between the crank-connected lever and the pull-O, a rock-lever, a cam for rocking it, and a loose, shifting connection between the crank-connected lever and the rock-lever.

6. In a buttonhole-sewing machine, of the character described, and having a hook-drivv ing shaft, the combination of a rotary cam, a rock-shaft, a lever on said rock-shaft in contact with said cam, a crank on said rock-shaft, a lever connected to said crank, an underthread pull-off connected with said crankconnected lever, a rock-lever to which the crank-connected lever is attached, a cam, a connection between the cam and rock-lever, and gearing connecting the said cam and hook-driving shaft and proportioned to impart one revolution of the cam to two of the shaft.

7. In a buttonhole-sewing machine, of the character described, a throat-plate having a needle-aperture, a thread-guard plate also having a needle-aperture which is alined with the needle-aperture in the throat-plate and below it, a pivoted under-thread pull-off having a thread-engaging Enger provided with a needle-opening and arranged between the throat-plate and the thread-guard plate,

and means to vibrate said pull-off across the said apertures.

' In testimony whereof we have hereunto set our hands this 5th day of January, A. D.

DONALD NOBLE. JOHN S. FINCH; Witnesses:

E. L. TOLLES, E. C. BAILEY. 

